TO: ALL WOOD COUNTY ARES MEMBERS (OFFICIAL)
ALL ARES AND NON-ARES AMATEURS ANYWHERE (INFORMATION)
FROM: KEN HARRIS WA8LLM ARRL DISTRICT 3
EMERGENCY COORDINATOR WOOD COUNTY EMERGENCY COMMUNICATIONS INC.
WOOD COUNTY ARES BULLETIN NR 19.47 DATE: November 24, 2019
SUBJECT: THE SOUNDCARD INTERFACE
In the last bulletin you learned what a soundcard and soundcard programs are, now you will know how to use them to connect to your radio for digital communications.
There are at least three ways to connect your computer to your transceiver to take advantage of soundcard programs. Some of the older desktop and laptop computers had a serial port in the form of a 9-pin plug. Using certain pins on the plug you could connect them to the Push-To-Talk (PTT) of the transceiver, and then use the audio jacks of the computer to connect to the speaker and microphone jacks of the transceiver.
Another way is to use the audio tones coming out of the computer soundcard jacks to operate the transceiver PTT. The audio coming out of the soundcard jacks can be amplified to a higher level using a soundcard-to-radio interface. Since the higher level tones are in the form of an Alternating Current sine wave, they can be converted to a Direct Current (DC) signal. The DC signal can be used to cause a transistor or relay to operate the transceivers PTT.
At the same time a sample of the computer soundcard audio tone can be sent to the transceiver microphone jack, to be transmitted of the air. When the computer is being used to receive audio from the radio, all it has to do is go back into the Microphone, or Line In jack of the computer, and the soundcard program converts the tones back into written words.
The computer-to-transceiver interface is a very simple unit and it can be either purchased or build. In any case using soundcard programs can be fun, and with the proper Amateur Radio license, you can communicate around the world with very little power.
A third way to interface your computer to your transceiver is to use the VOX (Voice Operated Transmit) function, if it has one. The audio coming out of the computer will cause the transceiver to start transmitting when it hears the tones. With VOX, the computer-to-radio interface is much simpler only needs a couple audio transformers.
Ken Harris WA8LLM
Wood County WV